JP5157013B2 - Tensioner - Google Patents

Description

  The present invention relates to a tensioner for adjusting the tension of an endless belt or chain so as to keep it constant.

  The tensioner, for example, pushes a timing chain or timing belt used in an automobile engine with a predetermined force, and acts to keep the tension constant when the chain is stretched or loosened.

  FIG. 23 shows a state in which the tensioner 100 is mounted on the engine body 200 of the automobile. A pair of cam sprockets 210 and a crank sprocket 220 are arranged inside the engine body 200, and a timing chain 230 is stretched between the sprockets 210 and 220 in an endless manner. A chain guide 240 is swingably disposed on the moving path of the timing chain 230, and the timing chain 230 slides on the chain guide 240. A mounting surface 250 is formed in the engine body 200, and the tensioner 100 is inserted into a mounting hole 260 formed in the mounting surface 250 and is fixed to the mounting surface 250 by a bolt 270. Note that lubricating oil (not shown) is sealed inside the engine body 200.

  A conventional tensioner includes a cylindrical propelling member that protrudes forward and backward toward a traveling chain, a case in which a sliding hole into which the propelling member is removably inserted is provided concentrically with the propelling member, A propulsion spring that urges the propulsion member in the protruding direction with respect to the case and a recess that is concentrically provided on the tip opening side of the sliding hole and is fitted to the propulsion member to be displaced in the axial direction of the propulsion member And a holder member provided concentrically with the recess, a holder spring for urging the holder member in the protruding direction of the propulsion member, and sliding in a sloped cam slope formed on the holder member A plurality of locking pieces that respectively mesh with a plurality of locking teeth engraved on the outer periphery of the member, and a cam guide that externally fits to the propelling member within the sliding hole and restricts the engagement of the plurality of locking pieces. Ring and said While fitted retractably an advance member and a sealing plate movably enclosing sequentially disposed the holder spring and the holder member and the locking pieces and the cam guiding ring into the recess of said slide hole. In this tensioner, when the chain is extended during operation of the engine, the propelling member is sequentially moved forward by one tooth to maintain an appropriate chain tension (see, for example, Patent Document 1).

  In the tensioner having the above structure, the propulsion member is urged in the advancing direction by the propulsion spring, and the locking piece expands and moves in the advancing direction while overcoming the locking teeth of the propelling member. Further, the propulsion member is locked while being locked back by the locking piece being pressed by the cam slant surface in the retreating direction and reduced in diameter and meshed with the engaging teeth of the propulsion member.

When attached to the engine body, the propulsion member advances to a position where appropriate chain tension can be obtained, prevents excessive return while receiving vibration from the chain guide, and if an excessive load is applied, the holder member Retracts and the holder spring bends to keep the chain tension properly. In addition, when the chain is extended due to long-term use, the propulsion member is appropriately advanced as the chain guide advances, so that an optimum chain tension is obtained.
Japanese Patent No. 3717473

  24 (a) is a longitudinal sectional view of a conventional tensioner having the same configuration as that of Patent Document 1, FIG. 24 (b) is a side view thereof, and FIG. 25 (a) is a state in which the propulsion member of the tensioner in FIG. Operation explanatory diagram in the locked state, (b) is a sectional view taken along the line DD of (a), FIG. 26 (a) is an operational explanatory diagram of the locking piece diameter-expanded state when the propelling member is advanced in FIG. ) Is a cross-sectional view taken along line EE in FIG. In these drawings, reference numeral 310 denotes a propulsion member, 320 denotes a locking piece, 330 denotes a holder member, 340 denotes a propulsion spring, and 350 denotes the locking piece 320 to be pressed against the cam inclined surface 330a of the holder member 330 to engage the propulsion member 310. A pressing spring urging in the diameter-reducing direction so as to be inserted, 360 is a holder spring, and 370 is a case.

  In the conventional tensioner, components are arranged concentrically in the order of the propelling member 310 → the locking piece 320 → the holder member 330 → the case 370 from the center of the shaft. Usually, the outer diameter of the case 370 is determined in accordance with the diameter of the mounting hole 260 of the engine body 200 (FIG. 23), and therefore the outer diameter of the engaging portion 310b of the propelling member 310 tends to be narrow due to the component arrangement. . In a high-power engine or the like, vibration from the cam chain is large, and the outer diameter of the propelling member 310 needs to be proportionally increased so as to increase the locking area of the propelling member 310 and the locking piece 320 in order to withstand the excessive load. There is. However, when the outer diameter of the propelling member 310 is increased, the outer diameter of the case 370 is increased and cannot be inserted into the predetermined mounting hole 260, so that there is a problem that the degree of freedom in design is small.

  When the propelling member 310 advances, the diameter of the locking piece 320 increases in the outer diameter direction along the cam inclined surface 330a of the holder member 330 when the locking piece 320 crosses a mountain and meshes with the next locking tooth. If the height h of the locking teeth is c and the diameter c is larger than the crest, a clearance C slightly larger than c is provided inside the holder member 330 so that it can be surely exceeded even if there is a variation in product dimensions. This is necessary (FIGS. 25 and 26), and the outer diameter of the case 370 increases accordingly. When two locking pieces 320 are arranged opposite to each other, 2C is required.

  Further, the locking piece 320 has a no-back design, and a return operation cannot be expected in the backward direction of the propelling member. The distance between the crankshaft on which the timing chain 230 is hung and the camshaft fluctuate due to the hot expansion of the engine body (block) 200 due to the temperature change inside the engine (FIG. 23). Paste. When the temperature is low, the timing chain 230 is loosened. Therefore, when the propulsion member 310 is located at a position where the locking piece 320 crosses one mountain and meshes with the next locking tooth or not, the backlash causes mainly “ A mechanical contact sound is generated. Conversely, when the temperature is high, the timing chain 230 is stretched and pushes the propelling member 310 in the backward direction. At this time, the locking piece 320 is completely engaged with the propelling member 310, and even if the propelling member 310 is pushed by the timing chain 230, the propelling member 310 cannot be retracted, and an overload that exerts an excessive tension on the timing chain 230. It becomes a state. In such a situation, the contact noise is reduced by reducing the pitch of the locking teeth, and the overload prevention is performed by the contraction of the holder spring 360 installed on the back surface of the holder member 330 to prevent overload. Yes. However, if the pitch of the locking teeth is too fine, the peak height h of the locking teeth becomes low, and the degree of freedom in design is limited, for example, the strength of the locking teeth is reduced.

  Further, the conventional tensioner requires a case 370 for arranging the propulsion member 310, the locking piece 320, the holder member 330, the propulsion spring 340, the pressing spring 350, and the holder spring 360, and the shape thereof is complicated. There was a problem such as a complicated structure.

  The present invention has been made to solve such problems. The structure is simplified, the locking teeth are increased in strength, the backlash is reduced, the number of parts is reduced, and the cost is reduced. Aim to provide a large tensioner.

  In order to achieve the above object, the tensioner according to the first aspect of the present invention includes a cylindrical member in which a plurality of locking teeth are formed, and one or a plurality of locking teeth that are engaged with the locking teeth. A locking piece, a locking piece receiving portion or a locking piece support portion for receiving the locking piece that engages with the cylindrical member, and a shaft member disposed inside the cylindrical member, Either the cylindrical member or the shaft member is a propulsion member that propels forward and backward by an urging force, and the locking piece moves in the diameter reducing direction to get over the locking teeth of the cylindrical member. Accordingly, a ratchet mechanism is provided that allows the propulsion member to advance, and that the locking piece moves in the diameter increasing direction and engages with the locking teeth of the cylindrical member to restrain the propulsion member from moving backward. It is characterized by.

  In the conventional tensioner, when the propulsion member propels, the movable space necessary for the pair of locking pieces to get over the locking teeth is required in the conventional tensioner at two locations 2C in the outer circumferential direction (see FIG. On the other hand, in the invention of claim 1, since the locking piece moves in the reduced diameter direction and gets over, there is no need to provide the gap C in the outer peripheral direction. Furthermore, since it is not necessary to provide the holder member 330 (FIG. 24) in the conventional tensioner, when the outer diameter of the case body is the same as that of the conventional tensioner, these radial dimensions are increased by the diameter of the cylindrical member. It becomes possible to allocate to. When the diameter of the cylindrical member is increased, the rigidity against a lateral load is increased. Moreover, when it is set as the outer diameter of the same cylindrical member as the conventional tensioner, the intensity | strength of the locking tooth of a locking piece and a cylindrical member inner surface can be set to the dimension which can endure a big load. On the other hand, when the inner diameter of the cylindrical member is made equal to the outer diameter of the propulsion member of the conventional tensioner, the entire tensioner is made thin despite the fact that the locking teeth and the locking teeth on the inner surface of the cylindrical member have the same strength. Can be made compact.

  Invention of Claim 2 is the tensioner of Claim 1, Comprising: The said ratchet mechanism is formed in the said locking piece receiving part, The direction which engages the said locking piece with the locking tooth of the said cylindrical member A cam slope formed so as to be expanded in diameter, and a pressing spring that presses the locking piece against the cam slope of the shaft member and biases it in the diameter-expanding direction.

  In the second aspect of the invention, the ratchet mechanism with a simple structure using the cam slope of the shaft member and the pressing spring increases the diameter of the locking piece and engages with the locking tooth of the cylindrical member, so that the propulsion member is retracted. to bound. Further, the pressing spring presses the locking piece against the cam slope of the shaft member and biases it in the diameter increasing direction, so that the locking piece and the locking teeth of the cylindrical member can be engaged without rattling. .

  A third aspect of the present invention is the tensioner according to the first or second aspect, wherein the ratchet mechanism is formed in the locking piece support portion, the locking piece receiving groove for receiving the locking piece, and the engagement member. It is characterized by comprising a support shaft for pivotally supporting the locking piece in the stopping piece receiving groove so as to be swingable in the radial direction, and a pressing spring for urging the locking piece in the radial direction.

  In the invention according to claim 3, the locking piece is provided by a ratchet mechanism having a simple structure in which the locking piece is pivotally supported in the radial direction by the support shaft and the pressing spring in the locking piece receiving groove of the shaft member. The diameter is expanded and engaged with the locking teeth of the cylindrical member, and the backward movement of the propelling member is restrained. Further, the pressing spring presses the locking piece against the cam slope of the shaft member and biases it in the diameter increasing direction, so that the locking piece and the locking teeth of the cylindrical member can be engaged without rattling. .

  A fourth aspect of the present invention is the tensioner according to any one of the first to third aspects, wherein the cylindrical member and the locking teeth of the locking piece are leads formed in a groove shape perpendicular to the axial direction. It is one of 0 flat teeth, 1 or multi-threaded teeth.

  5. The ratchet function according to claim 4, wherein when the locking teeth of the cylindrical member and the locking piece are the flat teeth of the lead 0, the processing is easy and can be engaged and disengaged without relative rotation of the locking piece and the cylindrical member. Is obtained. The threaded teeth can ensure a predetermined strength. The single thread with the same pitch and lead can be used for ordinary general-purpose screw processing, and the pitch can be reduced to prevent rattling of the locking pieces and the locking teeth of the cylindrical member. In a multi-thread screw whose integrated value with the number of threads is a lead, the pitch can be further reduced to further prevent rattling of the locking pieces and the locking teeth of the cylindrical member.

  A fifth aspect of the present invention is the tensioner according to any one of the first to fourth aspects, wherein the outer surface of the shaft member is movable relative to the inner surface of the cylindrical member in the axial direction via a radial gap. It is characterized by being arranged.

  In the fifth aspect of the invention, in order to reduce the radial gap between the inner surface of the cylindrical member and the outer surface of the shaft member, the shaft member is supported by the cylindrical member so as to be movable back and forth in the longitudinal direction. Strength against input (lateral load) can be increased. In addition, when hydraulic pressure is applied to the cylindrical member, a sealing function can be provided by setting a gap suitable for the seal. Furthermore, when it is necessary to improve the sealing performance, a sealing member can be incorporated between the inner surface of the cylindrical member and the outer surface of the shaft member to ensure the hydraulic sealing performance.

  A sixth aspect of the present invention is the tensioner according to any one of the first to fifth aspects, further comprising a hydraulic pressure source that applies hydraulic pressure in a direction propelled by the propulsion member.

  In the invention described in claim 6, since the propulsive force of the propulsion member is increased by applying hydraulic pressure in the propulsion direction of the propulsion member from the hydraulic pressure source, a small propulsion spring having a low compression force is used accordingly. be able to. In addition, viscous hydraulic oil adds damping and lubrication effects due to the hydraulic oil's viscous resistance to the operation of movable members such as propulsion members and locking pieces, thus stabilizing the amplitude of the propulsion member when it moves back and forth. Thus, the wear of these movable members can be suppressed, and the durability can be improved.

  According to the present invention, the locking piece and the shaft member are accommodated in the cylindrical member, arranged in the order of the shaft member, the locking piece, and the cylindrical member from the axial center toward the outer peripheral direction, and the locking piece has a reduced diameter. Since it moves in the direction and gets over, it is not necessary to provide the gap C in the outer peripheral direction, and it is not necessary to provide a holder member, so that the diameter of the cylindrical member can be appropriately selected. Therefore, even if the outer diameter of the cylindrical member is the same as that of the conventional tensioner, if the cylindrical member is increased in diameter, it is possible to increase the rigidity against the lateral load, and the locking piece and the cylindrical shape can be increased. The strength of the locking teeth on the inner surface of the member can be set to a size that can withstand a large load. When the inner diameter of the cylindrical member is made equal to the outer diameter of the propulsion member of the conventional tensioner so that the locking teeth and the locking teeth of the cylindrical member have the same strength, the entire tensioner is more than the conventional tensioner. It is also possible to make it thinner and more compact.

  Therefore, according to the present invention, it is possible to provide a tensioner that has a simple design, can increase the strength of the locking teeth, reduce backlash, reduce the number of components, and reduce the cost, and has a high degree of design freedom.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for implementing a tensioner of the present invention will be described in detail with reference to the drawings.
[Embodiment 1]

  1A is a longitudinal sectional view showing a tensioner according to Embodiment 1 of the present invention, FIG. 1B is a right side view thereof, FIG. 1C is a sectional view taken along line AA in FIG. FIG. 3A is a side view (partially longitudinal sectional view) of the shaft member of the first embodiment, and FIGS. 3B and 3C are plan views thereof. 4A is a side view (upper half vertical sectional view) of the locking piece of the first embodiment, and FIGS. 4B and 4C are its left side view, right side view, and FIG. 5A. These are the side view of the rotation prevention board of Embodiment 1, (b) and (c) are the top view and left view.

  The tensioner of Embodiment 1 is a cylindrical member 1 that is a propulsion member having a plurality of locking teeth 1b formed on a hollow inner surface, and a pair of cleave nuts that engage with the locking teeth 1b on the inner surface of the cylindrical member 1. The locking member 2 and the tubular member 1 are loosely fitted in the hollow of the cylindrical member 1 and have a locking piece receiving portion for receiving the locking piece 2 on the outer peripheral side of the distal end portion. The pushing spring 4, the pressing spring 5 that urges the locking piece 2 in the direction of the locking piece receiving portion of the shaft member 3, the holder spring 6 that urges the shaft member 3 in the pushing direction of the tubular member 1, and the tubular member 1. This is generally composed of a bottomed hollow case 7 or the like that is inserted and retracted freely.

  The case 7 is formed in a substantially bottomed cylindrical shape having a flange portion 7b at an intermediate portion of the body portion 7a. A housing hole 7c extending in the axial direction (propulsion direction) is formed in the body portion 7a toward the tip portion. The distal end portion of the storage hole 7c is open, and an assembly of the cylindrical member 1, the locking piece 2, the shaft member 3, the propulsion spring 4, the pressing spring 5, and the holder spring 6 is received in the storage hole 7c. Is done. A holding bolt 16 having a shaft-shaped guide portion 16a whose tip portion is thinner than the screw diameter is screwed into the screw hole 7f formed in the rear end bottom portion 7e of the case 7.

  The flange portion 7b of the case 7 is to be attached to the engine main body 200, and an attachment hole 7d through which a bolt 270 (FIG. 23) to be screwed into the engine main body 200 is formed. At the time of attachment to the engine main body 200, as shown in FIG. 23, the front end surface of the flange portion 7b abuts on the attachment surface 250 of the engine main body 200.

  The cylindrical member 1 has a rear end 1c that is open, has a closing wall 1a at the tip, and is formed with locking teeth 1b that engage with a pair of locking pieces 2 on the inner surface. When the tensioner is attached to the engine main body 200, as shown in FIG. 23, the tip end surface of the closing wall 1a of the cylindrical member 1 is attached in contact with the belt or chain guide 240.

  A propulsion spring 4 made of a compression spring member is disposed near the inner surface of the housing hole 7c of the case 7 between the rear end 1c surface of the cylindrical member 1 and the inner surface of the rear end bottom portion 7e of the case 7. When urged by the propulsion spring 4, the cylindrical member 1 protrudes from the case 7 and propels in the axial direction.

  As shown in FIGS. 1 and 3, the shaft member 3 has a guide hole 3 b drilled from the center of a flange 3 a provided at the rear end, and the guide hole 3 b is attached to the bottom 7 e of the case 7. The holding bolt 16 is inserted into the guide portion 16 so as to freely advance and retract. A conical cam slope 3c that gradually decreases in diameter in the propulsion direction is formed on the outer peripheral side of the tip of the shaft member 3, and a parallel cut surface 3d and a groove 3e are connected to the rear thereof. The cam slope 3c is a locking piece receiving portion that receives a pair of split nut-like locking pieces 2 described later.

  The shaft member 3 formed in this way is inserted into the tubular member 1 so that the distal end side of the flange 3a is relatively movable in the axial direction. In this case, the outer diameter of the shaft member 3 is set to be slightly smaller than the inner diameter of the locking teeth 1b in the tubular member 1. When the radial gap between the inner surface of the cylindrical member 1 and the outer surface of the shaft member 3 is reduced and hydraulic pressure is applied to the cylindrical member 1, the inner surface of the rear end 1c of the cylindrical member 1 and the outer surface of the shaft member 3 The sealing member 12 can be incorporated between the two to ensure the hydraulic sealing performance.

  A holder spring 6 made of a compression spring is disposed between the rear end surface of the flange 3 a of the shaft member 3 and the inner surface of the rear end bottom 7 e of the case 7. The shaft member 3 is biased in the propelling direction of the tubular member 1 by the holder spring 6. For this reason, when an overload from the engine is applied, a force in the backward direction of the shaft member 3 that receives the locking piece 2 engaged with the locking tooth 1b of the cylindrical member 1 by the cam inclined surface 3c is received. The holder spring 6 is compressed and the shaft member 3 moves backward. This ensures overload prevention.

  As shown in FIGS. 1, 2 and 4, the locking piece 2 has a shape having a parallel cut surface 2d obtained by cleaving a cylindrical nut having locking teeth 2a formed on the outer periphery. A cam cone 2b having a partially conical surface that is gradually reduced in diameter in the propelling direction of the cylindrical member 1 is formed on the inner peripheral side of the rear end of the locking piece 2, and a small-diameter step portion 2c having a partially cylindrical surface is formed at the tip. ing. The cam slope 2b has a shape that fits slidably in accordance with the cam slope 3c of the shaft member 3. Also in this embodiment, two pairs of locking pieces 2 are opposed to each other with the central axis interposed therebetween.

  An anti-rotation plate 8 that engages with the parallel cut surface 3d of the distal end portion of the shaft member 3 and the locking piece 2 to restrain the relative rotation of the shaft member 3 and the locking piece 2 is disposed inside the distal end of the tubular member 1. Has been.

  As shown in FIG. 5, the anti-rotation plate 8 has a center hole 8d, a flange portion 8b having parallel cut surfaces formed on both sides thereof, and is bent at a right angle continuously to the parallel cut surfaces of the flange portion 8b. A pair of parallel arms 8a extending in the direction of a pair and a rear end portion of the pair of arms 8a are formed by a thin plate member made up of claw portions 8c that are bent at right angles to face each other in the axial direction. The shaft member 3 and the parallel cut surfaces 3d and 2d of the locking piece 2 are both sandwiched and accommodated between the pair of parallel arms 8a, and the rear end claw portion 8c is fitted in the groove 3e at the front end portion of the shaft member 3. At the same time, the flange portion 8b at the front end is fitted into the hollow end of the cylindrical member 1. Although the locking piece 2 can move along the inner surface of the parallel arm 8a in the axial direction of the cylindrical member 1 with respect to the rotation preventing plate 8, the relative rotation of the shaft member 3 and the locking piece 2 is restricted. Become.

  As shown in FIGS. 1 and 2, a pressing spring 5 made of a compression spring member is disposed between the small-diameter step portion 2 c of the locking piece 2 and the flange portion 8 b of the rotation prevention plate 8. The locking piece 2 is constantly urged by the pressing spring 5 in the direction in which the locking piece 2 is pressed against the cam slope 3 c of the shaft member 3. In this way, the pressing spring 5 always presses the locking piece 2 against the cam inclined surface 3c of the shaft member 3 and biases it in the diameter increasing direction, whereby the locking piece 2 and the locking teeth 2a of the tubular member 1, Engagement with reduced backlash of 1b without backlash is ensured.

  The locking piece 2 and the locking teeth 2a and 1b of the cylindrical member 1 are either a flat tooth (rack) of the lead 0 formed in a groove shape perpendicular to the axial direction, or one or multiple threaded teeth Can be configured.

  When the locking teeth 2a and 1b are flat teeth of the lead 0, a ratchet function that can be engaged and disengaged without relative rotation of the locking piece 2 and the cylindrical member 1 is obtained. While securing a predetermined strength with the thread-like teeth, the single-thread screw can reduce the pitch to prevent rattling of the locking teeth 2a, 1b, and the multi-thread screw can further reduce the pitch to reduce the locking tooth 2a, The rattling of 1b can be further prevented.

  In this embodiment, the locking piece 2, the shaft member 3, the pressing spring 5, and the rotation prevention plate 8 are accommodated in the cylindrical member 1, and the shaft member 3, the locking piece 2, and the cylinder from the axial center toward the outer peripheral direction. The members 1 are arranged in this order, and are arranged in the housing holes 7 c of the case 7 with the locking pieces 2 and the tubular members 1 engaged with each other.

  In the tensioner of the first embodiment described above, the cylindrical member 1 moves in the direction of diameter reduction of the locking piece 2 in the propelling direction, and the locking tooth 2a gets over the locking tooth 1b on the inner surface of the cylindrical member 1, thereby the cylinder. The cylindrical member 1 can be propelled, and has a ratchet mechanism in which the backward movement of the cylindrical member 1 is restrained by engagement with the locking piece 2 and the locking teeth 2a and 1b of the cylindrical member 1. ing.

  The ratchet mechanism includes a shaft member 3 for expanding the diameter of the locking piece 2 in a direction in which the locking piece 2 is engaged with a locking tooth 1b on the inner surface of the cylindrical member 1, cam inclined surfaces 3c and 2b of the locking piece 2, and the locking piece 2 as a shaft. And a pressing spring 5 that presses against the cam slant surface 3c of the member 3 and biases it in the diameter increasing direction. When the cylindrical member 1 is propelled, the locking piece 2 moves in the reduced diameter direction along the cam inclined surface 3c of the shaft member 3 against the pressure on the cam inclined surface 3c, and the locking teeth 2a are cylindrical. The cylindrical member 1 can be propelled by overcoming the locking teeth 1b on the inner surface of the member 1. When the cylindrical member 1 moves backward, the locking piece 2 is pressed against the cam slope 3c of the shaft member 3 and moves in the diameter increasing direction, and the locking teeth 2a of the locking piece 2 are engaged with the inner surface of the cylindrical member 1. Retraction is constrained by engaging the stop teeth 1b.

  A more detailed operation of the tensioner of the present invention will be specifically described in Embodiment 2, which basically has the same configuration as that of Embodiment 1.

  In the first embodiment configured as described above, the locking piece 2 and the shaft member 3 are accommodated in the cylindrical member 1, and the shaft member 3, the pair of locking pieces 2, and the cylindrical shape from the axial center toward the outer peripheral direction. The members 1 are arranged in this order. As a result, the space required for the locking piece 2 to get over the locking teeth 1b on the inner surface of the cylindrical member 1 when the cylindrical member 1 is propelled requires two 2Cs in the outer circumferential direction in the conventional tensioner. On the other hand, in this embodiment, since the locking piece 2 moves in the reduced diameter direction and gets over, there is no need to provide the gap C in the outer peripheral direction. Furthermore, since there is no need to provide the holder member 330 of the conventional tensioner, when the outer diameter of the case body 7a is the same as the outer diameter d5 of the case body of the conventional tensioner (see FIG. 24), these The radial dimension can be applied to the diameter increase of the tubular member 1.

  Increasing the diameter of the cylindrical member 1 has the effect of increasing the rigidity against lateral loads. When the outer diameter of the cylindrical member 1 is the same as the outer diameter d5 of the case barrel of the conventional tensioner, The strength of the locking teeth 2a and 1b on the inner surface of the stop piece 2 and the cylindrical member 1 can be set to a size that can withstand a large load. On the other hand, when the inner diameter d1 of the cylindrical member 1 is made equal to the outer diameter d1 of the conventional tensioner propulsion member, the compact tensioner 2a and 1b have the same strength even though the locking teeth 2a and 1b have the same strength. Is possible.

  Table 1 shows a comparison of main part dimensions (unit: mm) with a conventional tensioner. The symbols are as shown in FIGS.

  When the outer diameter d5 of the body portion 7a of the conventional case is 20 mm, the first example of the present invention is such that the inner diameter d1 of the cylindrical member 1 is equal to the outer diameter d1 of the locking teeth of the conventional propulsion member. is there. In this case, the outer diameter d5 of the body portion of the case of the conventional product needs to be about 20 mm, but may be about 16 mm in the example of the present invention. Thus, the present invention can be made compact, and can withstand a larger load when the outer diameter d5 of the body portion 7a is the same as that of the conventional product.

In the two examples of the present invention, the outer diameter d5 of the body portion 7a is set to the same diameter as that of the conventional product. In this case, the outer diameter d1 of the locking tooth 1b of the cylindrical member 1 can be increased to 12 mm with respect to 8 mm of the conventional product. The reason is as described above.
[Embodiment 2]

  6A is a longitudinal sectional view showing the tensioner according to the second embodiment of the present invention, FIG. 6B is a sectional view taken along line BB of FIG. 7A, and FIG. 7 is a main portion of the tip of the tensioner according to the second embodiment (ratchet mechanism). 8A is a side view of the shaft member of the second embodiment, FIG. 8B is a plan view thereof, FIG. 9A is a diagram of the second embodiment, and FIG. Side views of the stop piece, (b) and (c) are left side views and right side views thereof, FIG. 10 (a) is a side view of the rotation preventing plate of the second embodiment, and (b) and (c) are plan views thereof. FIG. 11A is a side view of the presser plate of the second embodiment, and FIG. 11B is a left side view thereof.

  In the second embodiment, the shape of the shaft member 3 in the first embodiment and the form of the attachment structure to the rear end of the case 7 are different, and a presser plate 9 is added between the locking piece 2 and the pressing spring 5. Other configurations are the same as those of the first embodiment except that the contact portion between the locking piece 2 and the presser plate 9 and the shape of the rotation prevention plate 8 are different. Therefore, these changes will be described below.

  In the case 7 of this embodiment, a projection 7g extending in the axial direction to the middle portion in the storage hole 7c is provided at the center of the rear end bottom portion 7e, and a guide hole 7h is opened at the center of the projection 7g. Other than this point, the configuration is the same as that of the first embodiment.

  The outer diameter of the protrusion 7 g of the case 7 is set slightly smaller than the inner diameter of the locking tooth 1 b in the cylindrical member 1. By reducing the radial gap between the inner surface of the cylindrical member 1 and the outer surface of the projection 7g, it serves as a seal when hydraulic pressure is applied to the cylindrical member 1. Furthermore, when high sealing performance is required, the sealing member 12 can be incorporated between the inner surface of the rear end 1c of the tubular member 1 and the outer surface of the projection 7g to ensure hydraulic sealing performance.

  As shown in FIGS. 6 and 8, the shaft member 3 is provided with a threaded portion 3 f at the rear end portion, and the shaft portion can be freely advanced and retracted into a guide hole 7 h of a protruding portion 7 g provided on the bottom portion 7 e of the case 7. In the inserted state, a nut 17 described later is screwed onto the screw portion 3f.

  On the outer peripheral side of the distal end portion of the shaft member 3, a conical cam inclined surface 3c that gradually decreases in the propulsion direction is formed with an umbrella-shaped step end surface 3g having a diameter larger than that of the shaft portion, and a parallel cut surface 3d. In addition, a small-diameter shaft portion 3h having a groove 3i formed continuously at the tip of the cam inclined surface 3c is formed. The cam slope 3c serves as a locking piece receiving portion that receives a pair of split nut-like locking pieces 2 described later. The outer diameter of the step portion 3g is set slightly smaller than the inner diameter of the locking tooth 1b in the cylindrical member 1. The functions of the parallel cut surface 3d and the small diameter shaft portion 3h will be described later.

  Also in the second embodiment, a holder spring 6 made of a compression spring is externally fitted to the shaft portion of the shaft member 3 between the rear end surface of the step portion 3g of the shaft member 3 and the front end surface of the protruding portion 7g of the case 7. Yes. The shaft member 3 is urged in the propelling direction of the tubular member 1 by the holder spring 6. As a result, when an overload from the engine is applied, the holder spring 6 that receives the force in the backward direction of the shaft member 3 that receives the locking piece 2 engaged with the cylindrical member 1 with the cam inclined surface 3c is compressed. Thus, the shaft member 3 moves backward. This can prevent overload.

  As shown in FIGS. 6, 7 and 9, the locking piece 2 of the second embodiment has a shape having a parallel cut surface 2 d obtained by cleaving a cylindrical nut having a locking tooth 2 a engraved on the outer periphery. A cam cone 2b having a partially conical surface that gradually decreases in diameter in the propulsion direction of the cylindrical member 1 is formed on the inner peripheral side of the end, and a small conical surface-shaped step portion 2c that is gradually reduced in diameter in the propulsion direction is formed at the tip. Has been. The cam slope 2 b is formed in a shape that fits slidably in accordance with the cam slope 3 c of the shaft member 3. Also in this embodiment, a pair of the locking pieces 2 are arranged so as to face each other across the central axis.

  Further, the rotation prevention plate 8 that engages with the parallel cut surface 3 d at the tip of the shaft member 3 and the locking piece 2 to restrain the relative rotation of the shaft member 3 and the locking piece 2 is provided with a small diameter at the tip of the locking piece 2. It is fixed to the step 2c.

  As shown in FIG. 10, the anti-rotation plate 8 has a center hole 8d and is bent at a right angle continuously to the flange portion 8b having parallel cut surfaces 8e formed on both sides thereof and the parallel cut surface 8e of the flange portion 8b. It is integrally formed by a thin plate member consisting of a pair of parallel arms 8a extending in the axial direction. The shaft member 3 and the parallel cut surfaces 3d and 2d of the locking piece 2 are both sandwiched between the pair of parallel arms 8a and accommodated in a close contact state. As shown in FIG. 6, the flange portion 8b at the front end is fitted into the small-diameter step portion 2c of the locking piece 2 inserted through the small-diameter shaft portion 3h of the shaft member 3 through the hollow hole 8d. The locking piece 2 can be moved integrally with the rotation preventing plate 8 in the axial direction of the cylindrical member 1 by the rotation preventing plate 8, but the relative rotation of the shaft member 3 and the locking piece 2 is restricted. It becomes a state.

  As shown in FIGS. 6 and 7, a presser plate 9 that holds the pressing spring 5 is interposed between the partially conical small-diameter stepped portion 2 c of the locking piece 2 and the inner surface of the closed wall 1 a at the tip of the cylindrical member 1. The shaft member 3 is disposed so as to be movable in the axial direction on the small-diameter shaft portion 3h at the tip end portion.

  As shown in FIGS. 6 and 11, the presser plate 9 has an outer flange portion 9b at the front end portion of a substantially cylindrical body, and an inner flange portion 9d having a central circular hole 9a formed at an axially intermediate portion of the inner surface. In addition, a conical cam inclined surface 9c that is gradually reduced in diameter in the propulsion direction is formed at the tip.

  The presser plate 9 has a concentric circular hole 9a slidably fitted to the small diameter shaft portion 3h of the shaft member 3, and engages with the groove 3i of the small diameter shaft portion 3h. Is prevented from coming off from the tip of the small diameter shaft portion 3h. The cam inclined surface 9c of the presser plate 9 is formed in a shape corresponding to the partial conical surface-shaped small-diameter step portion 2c of the locking piece 2 and is pressed against and pressed, so that when the tubular member 1 advances, The locking piece 2 prompts the movement in the direction of diameter reduction.

  Further, as shown in FIGS. 6 and 7, there is compression between the front surface of the flange portion 8 b of the rotation prevention plate 8 fitted to the small diameter step portion 2 c of the locking piece 2 and the rear surface of the outer flange portion 9 b of the presser plate 9. A pressing spring 5 made of a spring is arranged on the outer periphery of the cylindrical body of the pressing plate 9. The locking piece 2 is constantly urged by the pressing spring 5 in a direction in which the locking piece 2 is pressed against the cam slope 3 c of the shaft member 3. In this way, the pressing spring 5 always presses the locking piece 2 against the cam inclined surface 3c of the shaft member 3 and biases it in the diameter increasing direction, whereby the locking piece 2 and the locking teeth 2a and 1b of the tubular member 1 are obtained. Engagement with reduced backlash without rattling can be ensured.

  In the second embodiment, the locking piece 2, the shaft member 3, the pressing spring 5, the rotation prevention plate 8, and the pressing plate 9 are accommodated in the cylindrical member 1, and the shaft member 3 and the engaging member are moved from the axial center toward the outer peripheral direction. The stop piece 2 and the cylindrical member 1 are arranged in this order, and are arranged in the housing hole 7c of the case 7 with the locking piece 2 and the cylindrical member 1 engaged. At this time, the nut 17 to be screwed into the threaded portion 3 f of the shaft member 3 in a state where the shaft portion of the shaft member 3 is fitted into the guide hole 7 h of the protruding portion 7 g of the case 7 is Tightening adjustment is performed so as to obtain a predetermined initial set compression force of the holder spring 6 that is externally fitted to the shaft portion and is elastically mounted between the step portion 3g and the protruding portion 7g of the case 7.

  Also in the second embodiment having the above-described configuration, similarly to the first embodiment, the cylindrical member 1 is moved by the ratchet mechanism, the locking piece 2 is moved in the reduced diameter direction in the propulsion direction, and the locking tooth 2a is the cylindrical member. 1 can be propelled by getting over the locking teeth 1b on the inner surface, and the backward movement is restrained by providing a locking function by engaging the locking pieces 2 and the locking teeth 2a, 1b of the tubular member 1 in the backward direction. The

  Also in the second embodiment, the locking piece 2 and the shaft member 3 are accommodated in the cylindrical member 1, and are arranged in the order of the shaft member 3, the locking piece 2 and the cylindrical member 1 from the axial center toward the outer peripheral direction. Since the locking piece 2 moves in the reduced diameter direction and gets over, there is no need to provide a necessary gap (2C: see FIGS. 25 and 26) in the outer peripheral direction of the conventional tensioner. For this reason, it becomes possible to apply to the diameter increase of the cylindrical member 1, and it can be set as the tensioner which can endure a big load in the intensity | strength of the locking piece 2 and the locking teeth 2a and 1b of the cylindrical member 1 inner surface. Further, the whole tensioner can be made compact while ensuring the predetermined strength of the locking teeth 2a and 1b.

  FIG. 12 shows the operation of the tensioner of the second embodiment, where (a) is an overload state during engine hot operation, (b) is an appropriate load state during normal engine operation, and (c) is during engine cold operation. The light load state is shown.

  The distance between the crankshaft on which the timing chain is applied and the camshaft fluctuates due to the hot expansion of the engine block due to the temperature change inside the engine, and the timing chain is pushed by loosening at low temperatures and stretching at high temperatures. As described above, an overload state during engine hot operation, an appropriate load state during normal operation, and a light load state during cold operation occur in the tensioner that is held.

  In the overload state during the engine hot operation shown in FIG. 12A, when the cylindrical member 1 that has received the overload from the timing chain moves backward, the locking piece 2 is connected to the cam slope 3c of the shaft member 3. The engaging teeth 1b of the cylindrical member 1 and the engaging teeth 2a of the engaging piece 2 are engaged with each other. In this state, when the shaft member 3 is pushed together with the cylindrical member 1 that accommodates them, the holder spring 6 is compressed and the umbrella-shaped step end surface 3g of the shaft member 3 is retracted to the position P1. At this time, the front end surface of the cylindrical member 1 is at the position P3.

  In the proper load state during normal engine operation shown in FIG. 12B, the locking teeth 1b of the cylindrical member 1 and the locking teeth 2a of the locking piece 2 that have received the appropriate load from the timing chain are engaged. Thus, the state without any play (gap) is maintained. At this time, the shaft member 3 advances from the position P1 to P2 of the umbrella-shaped step end face 3g in the overload state, and the tubular member 1 advances from the position P3 to P4 of the tip surface in the overload state. .

  In the light load state during cold engine operation shown in FIG. 12 (c), the cylindrical member 1 and the locking piece 2 that have received a light load from the timing chain begin to advance, and the locking piece 2 advances. However, it slides in the internal diameter direction shown by the arrow in FIG.12 (c), and the latching tooth 1b of the cylindrical member 1 and the latching tooth 2a of the latching piece 2 begin to remove | deviate from an engagement state. When the cylindrical member 1 further advances, the locking tooth 2a of the locking piece 2 gets over one locking tooth 1b of the cylindrical member 1, and again, both the locking teeth 2a as in the proper load action, 1b is engaged. At this time, the shaft member 3 remains at the position P2 of the umbrella-shaped step end surface 3g in the appropriate load state, and the position of the tip end surface of the tubular member 1 has advanced from P4 to P5 in the appropriate load state. .

The propulsion spring 4, the pressing spring 5, and the holder spring 6 that are compression spring members in the first and second embodiments described above have a relatively set compression force so as to satisfy the operation of the tensioner in the load state during engine operation. The balance is adjusted and incorporated in the cylindrical member 1.
[Embodiment 3]

  FIG. 13 is a longitudinal sectional view showing the tensioner according to the third embodiment of the present invention, and FIG. 14 is an exploded perspective view of a main portion (ratchet mechanism portion) of the tip of the tensioner according to the third embodiment.

  In the third embodiment, the entire assembly member accommodated in the case 7 in the first and second embodiments has a simple structure in which the case 7 and the holder spring 6 are omitted while being reversely arranged in the axial direction. The cylindrical member 1 is directly inserted into the mounting hole 260 of the engine body 200 and fixed, and the shaft member 3 is set as a propelling member so as to advance. Although the shapes of both ends of the cylindrical member 1 and the shaft member 3 are slightly different and the mounting structure of the cylindrical member 1 to the engine main body 200 is different, other configurations are basically the same as those of the second embodiment.

  The cylindrical member 1 according to the third embodiment has both ends opened, locking teeth 1b that engage with a pair of locking pieces 2 are formed on the entire inner surface, and an outer flange portion 1d at the rear end. Is provided. The barrel portion on the front side from the outer flange portion 1d of the tubular member 1 is inserted into the mounting hole 260 together with a holder spring 6 which will be described later, and the outer flange portion 1d is mounted on the mounting surface 250 of the engine body 200. The outer flange portion 1d is covered with the cap-shaped attachment lid 11 in a state where the outer flange portion 1d is in contact.

  As shown in FIG. 14, the cap-shaped attachment lid 11 is configured such that the bolt 21 inserted through the bolt attachment hole 11 b provided in the flange portion 11 a is screwed into the female screw hole 251 of the attachment surface 250 of the engine body 200. The outer flange portion 1 d of the member 1 is fixed to the mounting surface 250 of the engine main body 200.

  The shaft member 3 of Embodiment 3 protrudes from the tip 1c ′ of the cylindrical member 1 at the tip, and is provided with an outer flange 3a. The shaft portion on the rear side from the outer flange 3a is inserted into the cylindrical member 1, and The front end surface of the outer flange 3a abuts on a belt or chain guide (not shown) to propel it forward and backward. Also in this case, the outer diameter of the insertion portion of the shaft member 3 is set to be slightly smaller than the inner diameter of the locking tooth 1b in the cylindrical member 1. By reducing the radial gap between the inner surface of the tubular member 1 and the outer surface of the shaft member 3, the lateral load strength of the shaft member 3 and the tubular member 1 can be increased. Further, when hydraulic pressure is applied to the cylindrical member 1, it is possible to provide a sealing function by setting a gap suitable for sealing, and when it is necessary to improve sealing performance, The sealing member 12 can be incorporated between the inner surface of the tip end of the shaped member 1 and the outer surface of the shaft member 3 to ensure hydraulic sealing performance.

  On the outer peripheral side of the rear end portion of the shaft member 3, a conical cam inclined surface 3c that gradually increases in diameter in the propulsion direction is formed, and a small diameter shaft having a parallel cut surface (not shown) and a groove 3i formed in the rear end thereof. The part 3h is formed continuously. The cam slope 3c serves as a locking piece receiving portion for receiving a pair of split nut-like locking pieces 2 similar to the above embodiment.

  Installation of the engine main body 200 in a state in which a propulsion spring 4 made of a compression spring is externally fitted to the body portion of the tubular member 1 between the rear surface of the outer flange 3a of the shaft member 3 and the front surface of the outer flange portion 1d of the tubular member 1 It is disposed in the hole 260. By being urged by the propulsion spring 4, the shaft member 3 protrudes from the cylindrical member 1 and is propelled in the axial direction.

  In this embodiment, the holder spring 6 in the first and second embodiments is omitted. When an overload from the engine is applied, the cylindrical member 1 engaged with the locking piece 2 pressed against the cam inclined surface 3c receives the force in the backward direction of the shaft member 3, and the mounting lid 11 presses. It is also possible to design so that overload prevention is performed by deforming the mounting flange portion. However, this embodiment is suitable for a small and medium-sized engine that performs a relatively light load operation as compared with the first and second embodiments as a simplified type in which the holder spring for preventing overload is omitted.

  The locking piece 2 of the third embodiment is used by reversing the locking piece 2 in the first and second embodiments, and is a partial conical surface that gradually increases in diameter in the propulsion direction of the shaft member 3 on the inner peripheral side of the tip. A cam slope 2b is formed, and a small-diameter step 2c is formed at the rear end. Other shapes are the same as those of the first and second embodiments. Also in this embodiment, the locking pieces 2 are arranged in a pair (two) so as to face each other across the central axis.

  Also in this embodiment, the presser plate 9 is slidably fitted to the small-diameter shaft portion 3h of the shaft member 3, and the C-ring 10 engaged in the groove 3i of the small-diameter shaft portion 3h is behind the small-diameter shaft portion 3h. Falling off from the edge is prevented.

  Further, a pressing spring 5 made of a compression spring is disposed between the pressing plate 9 and a washer 8 ′ fitted to the small diameter step 2 c of the locking piece 2. The locking piece 2 is constantly urged by the pressing spring 5 in a direction in which the locking piece 2 is pressed against the cam slope 3 c of the shaft member 3. Thereby, the pressing spring 5 always presses the locking piece 2 against the cam inclined surface 3c of the shaft member 3 and urges it in the diameter increasing direction. By this, the engagement which reduced the backlash without the rattling of the locking piece 2 and the locking teeth 2a and 1b of the cylindrical member 1 can be ensured. In this embodiment, since the washer 8 ′ is provided in place of the rotation preventing plate 8 in the first and second embodiments, the locking piece 2 can rotate around the cam slope 3c of the shaft member 3. It has become.

  In the third embodiment configured as described above, the shaft member 3 is moved by the ratchet mechanism similar to the first and second embodiments, the locking piece 2 is moved in the reduced diameter direction in the propulsion direction, and the locking teeth 2a are the cylindrical members. 1 can be propelled by getting over the locking teeth 1b on the inner surface, and the backward movement is restrained by providing a locking function by engaging the locking pieces 2 and the locking teeth 2a, 1b of the tubular member 1 in the backward direction. The Then, the same operation as in the first and second embodiments can be performed in accordance with an appropriate load state during normal operation of the small engine and a light load state during cold operation.

  Also in the third embodiment, the locking piece 2 and the shaft member 3 are accommodated in the cylindrical member 1, and are arranged in the order of the shaft member 3, the locking piece 2 and the cylindrical member 1 from the axial center toward the outer peripheral direction. Since the locking piece 2 moves in the reduced diameter direction and gets over, there is no need to provide a gap (2C: see FIGS. 25 and 26) necessary in the outer peripheral direction in the conventional tensioner in the outer peripheral direction. For this reason, it becomes possible to apply to the diameter increase of the cylindrical member 1. Moreover, it can be set as the tensioner which can endure a big load with the intensity | strength of the latching teeth 2a and 1b of the latching piece 2 and the cylindrical member 1 inner surface. Further, it is possible to make the entire tensioner compact while ensuring the predetermined strength of the locking teeth 2a and 1b.

  In addition, in the third embodiment, since the case 7 and the holder spring 6 in the first and second embodiments are omitted, the structure of the tensioner can be simplified, and the size, weight, and cost can be reduced.

  15 is a longitudinal sectional view showing a tensioner according to a modification of the third embodiment, FIG. 16 (a) is a side view (partially longitudinal sectional view) of the shaft member of FIG. 15, and (b) and (c) are plan views thereof. It is a figure and a left view.

  In this modified embodiment, a configuration in which one locking piece 2 in the third embodiment is provided on one side with respect to the central axis, and a locking piece receiving portion-related configuration of the rear end portion of the shaft member 3 is associated therewith. Other configurations are the same as those of the third embodiment except that the shape is partially changed.

  On the outer peripheral side of the rear end portion of the shaft member 3 of this modified form, a cam groove 3j having a flat cam inclined surface 3c gradually expanding in the propulsion direction is formed at one place and a parallel cut surface (not shown) is formed. ing. The cam groove 3j has a groove width that slidably accommodates the locking piece 2, whereby the relative rotation of the locking piece 2 and the shaft member 3 is restricted, and the cam inclined surface 3c receives the locking piece 2. It is a locking piece receiving part.

  Therefore, in this modified embodiment, the rotation preventing plate 8 in the above embodiment is omitted, the configuration is further simplified, the cost can be reduced, and it is suitable for a small engine that performs a light load operation.

  The locking piece 2 of this modified form is a modified form of the locking piece 2 of the third embodiment that is used by reversing the locking piece 2 in the first and second embodiments, and its rear end is formed on a vertical surface. A wedge-shaped cleave having a parallel cut surface (not shown) in which a locking tooth 2a is engraved on the outer periphery, and a planar cam slope 2b is formed on the inner peripheral side. It is formed in a nut shape. The cam slope 2 b is formed in a slope shape that abuts corresponding to the cam slope 3 c of the shaft member 3.

  A screw hole 3k is formed in the rear end surface of the shaft member 3, and the presser plate 9 is fixed to the rear end surface of the shaft member 3 by a screw member 19 screwed into the screw hole 3k.

  Further, a pressing spring 5 made of a small-diameter compression spring is disposed between the pressing plate 9 and the rear end surface of the locking piece 2, and the front half of the pressing spring 5 is inserted into the cam groove 3 j of the shaft member 3.

Also in this modified embodiment having the above configuration, the same operations and effects as those of the third embodiment can be achieved.
[Embodiment 4]

  FIG. 17A is a side view (main part longitudinal sectional view) showing a tensioner according to a fourth embodiment of the present invention, FIG. 17B is a plan view thereof, and FIG. 18A is a plan view of a bracket according to the fourth embodiment. (B) is the left side view.

  The fourth embodiment is different from the third embodiment in the mounting structure of the rear end portion of the tubular member 1 to the engine body 200, and the tubular member 1 is filled with the hydraulic pressure 301 from the hydraulic source 300, and the shaft member 3 is The other configuration is the same as that of the third embodiment except that the hydraulic pressure 301 acts in the propulsion direction.

  In the tubular member 1 of the fourth embodiment, both end portions are open, locking teeth 1b that engage with a pair of locking pieces 2 are formed on the inner surface, and between the inner surface of the tip and the outer surface of the shaft member 3. The seal member 12 is mounted and a blind cover 14 is fitted on the inner surface of the rear end. In addition, a hydraulic flow port 1e is opened at the rear end of the tubular member 1, and the hydraulic pressure 301 from the hydraulic power source 300 provided on the engine body 200 side is supplied from the hydraulic flow port 1e to the inside of the cylindrical member 1. Filled.

  Similarly, in each of the above embodiments, the seal member 12 seals the hydraulic pressure in the tubular member 1 and has an effect of preventing the shaft member 3 from coming off. Therefore, if the shaft member 3 continues to advance, the locking member 2 a of the locking piece 2 incorporated in the cam slope 3 c at the rear end of the shaft member 3 abuts against the seal member 12, so that the shaft member 3 advances. Stopped.

  The tubular member 1 has two bolt members 20 attached by a U-shaped clamp 13 in a state where the lower outer surface of the rear end portion is disposed in a shallow concave mounting groove 202 formed in the inner wall 201 of the engine body 200. It is mounted via. At this time, a seal in which a hydraulic flow port 302 communicating with a hydraulic pressure source 300 provided on the engine body 200 side and a hydraulic flow port 1 e on the rear end body portion of the tubular member 1 are fitted around the hydraulic flow port 302. It is set so as to oppose and match each other via the member 303.

  As shown in FIGS. 17 and 18, the U-shaped clamp 13 has a claw portion 13e that is bent at a right angle downward (on the mounting surface 250 side) continuously to the rear side surface of the top portion of the central cylindrical surface portion 13a. Bolt mounting holes 13c through which the bolt members 20 are inserted are formed in the horizontal portions 13b at both ends. When the tubular member 1 is attached to the engine main body 200 by the U-shaped clamp 13, the claw portion 13e is in contact with the upper part of the rear end surface of the tubular member 1, and thereby the tip of the outer flange 3a of the shaft member 3 is contacted. The cylindrical member 1 which received the load from the belt which contact | abuts the surface or the chain guide 240 has the function to prevent sliding back.

  As shown in FIG. 17, the inner wall 201 of the engine body 200 is continuous with the mounting groove 202, and escapes from the outer flange 3 a of the shaft member 3 and the belt or chain guide 240 along the propelling direction of the shaft member 3. A unit 203 is provided.

  Further, the propulsion spring 4 is disposed between the front end surface of the tubular member 1 and the rear surface of the outer flange 3 a of the shaft member 3 in a state of being fitted on the body portion of the tubular member 1, and is urged by the propulsion spring 4. As a result, the shaft member 3 protrudes from the cylindrical member 1 and is propelled in the axial direction.

  Also in this embodiment, as in the third embodiment, the holder spring 6 for preventing overload in the first and second embodiments is omitted.

  In the fourth embodiment configured as described above, in addition to the same operations and effects as those of the third embodiment, the hydraulic pressure is applied in the propelling direction of the shaft member 3 in the tubular member 1 so that the shaft member 3 Since the propulsive force is increased, a small propulsion spring 4 having a low compressive force can be used accordingly. Further, the viscous hydraulic oil adds a damping effect and a lubrication effect due to the viscous resistance of the hydraulic oil to the operation of the movable member such as the shaft member 3 and the locking piece 2. The effect of stably suppressing the amplitude is enhanced, and the durability can be improved by suppressing the wear of these movable members.

For this reason, Embodiment 4 has a degree of freedom in design that can be applied from a small engine that performs a relatively light load operation to a medium engine that performs a medium load operation.
[Embodiment 5]

  FIG. 19A is a side view (main part longitudinal sectional view) showing a tensioner according to Embodiment 5 of the present invention, and FIG. 19B is a plan view thereof.

  The fifth embodiment is different from the fourth embodiment in the shape of the rear end portion of the tubular member 1 and the mounting structure to the engine main body 200. The shaft member 3 is divided into two parts and the holder spring 6 is mounted therebetween. Except for the point that the deformed structure is connected at, the other configuration is the same as that of the fourth embodiment in which the hydraulic pressure 301 is applied in the direction propelled by the shaft member 3.

  The cylindrical member 1 of the fifth embodiment has both ends opened, and locking teeth 1b that engage with a pair of locking pieces 2 are formed on the entire inner surface, and the tip inner surface and the outer surface of the shaft member 3 A seal member 12 is mounted between the two. The seal member 12 has an effect of sealing the hydraulic pressure in the cylindrical member 1 and preventing the shaft member 3 from coming off. A hexagonal nut 1d is formed on the outer surface of the rear end of the tubular member 1.

  The cylindrical member 1 according to this embodiment has a male screw portion formed by protruding a locking tooth 1b on the inner surface of the rear end portion from a step end portion 206 of a low step portion 205 formed in the inner wall 201 of the engine body 200. 207 is screwed. For this reason, when the cylindrical member 1 is attached to the main body 200 of the engine, the attachment members such as the U-shaped clamp 13 and the two bolt members 20 in the fourth embodiment can be omitted.

  The male threaded portion 207 of the engine body 200 has a hydraulic flow port 302 formed in the axial direction, and the hydraulic pressure 301 from the hydraulic pressure source 300 provided on the engine main body 200 side is filled into the cylindrical member 1 from the hydraulic flow port 302. Is done. Thereby, the hydraulic pressure 301 acts in the direction in which the shaft member 3 propels.

  The shaft member 3 according to the fifth embodiment is divided into a front shaft member 31 and a rear shaft member 32 which are connected by a connecting member 33 described later.

  The front shaft member 31 has a bottom 31b with a center hole 31c formed at the rear end, is formed in a bottomed cylindrical shape with an open front end, and is rearward from an outer flange 3a provided on the outer surface of the front end. The side shaft portion 31a is fitted and inserted into the cylindrical member 1, and the front end surface of the outer flange 3a protruding from the front end 1c of the cylindrical member 1 is brought into contact with the belt or the chain guide 240 so as to advance and retract freely. Also in this case, the outer diameter of the shaft portion 31 a is set slightly smaller than the inner diameter of the locking tooth 1 b in the tubular member 1. By reducing the radial gap between the inner surface of the cylindrical member 1 and the outer surface of the shaft portion 31a, the inner surface of the rear end of the cylindrical member 1 and the shaft portion 31a can be used when hydraulic pressure is applied to the cylindrical member 1. The seal member 12 provided between the outer surface and the outer surface secures the sealing performance of the hydraulic pressure 301 and prevents the front shaft member 31 from coming off from the tubular member 1.

  On the outer peripheral side of the rear end portion of the rear shaft member 32, a conical cam inclined surface 3c that gradually increases in diameter in the propulsion direction has an umbrella-shaped step end surface 3g having a diameter larger than that of the shaft portion 32a that continues from there. In addition, a parallel cut surface 3d and a small diameter shaft portion 3h having a groove 3i formed at the rear end thereof are continuously formed. The cam slope 3c serves as a locking piece receiving portion for receiving a pair of split nut-like locking pieces 2 as in the fourth embodiment. Further, a female screw hole 32b is formed in the axial direction at the center of the tip surface of the shaft portion 32a.

  In the state where the holder spring 6 is externally fitted to the shaft portion 32 a of the rear shaft member 32 between the umbrella-shaped step end surface 3 g of the rear shaft member 32 and the rear end surface of the front shaft member 31, the front shaft member 31. A bolt member (connecting member) 33 with a flange 33a that is slidably inserted into the center hole 31c of the rear end bottom portion 31b from the front end opening portion of the rear shaft member 32 is provided in the female screw hole 32b provided in the shaft portion 32a of the rear shaft member 32. Screwed. Thus, the front shaft member 31 is guided by the connecting member 33 with respect to the rear shaft member 32 while being urged by the holder spring 6 in the propulsion direction, and can move forward and backward in the axial direction. At the time of assembly, the predetermined mounting length of the holder spring 6 is adjusted by the hooked bolt member 33 so that a predetermined initial urging force (compression force) of the holder spring 6 is obtained.

  The propulsion spring 4 is disposed between the rear surface of the outer flange 3 a of the front shaft member 31 and the front end surface of the tubular member 1 in a state of being fitted on the body portion of the tubular member 1. By being urged by the propulsion spring 4, the connected shaft member 3 protrudes from the tubular member 1 on the outer flange 3 a side of the front shaft member 31 and propels it in the axial direction.

  Also in the fifth embodiment having the above-described configuration, as in the third and fourth embodiments, the shaft member 3 connected by the ratchet mechanism is locked by the locking piece 2 moving in the reduced diameter direction in the propulsion direction. The teeth 2a can be propelled by moving over the locking teeth 1b on the inner surface of the cylindrical member 1, and have a locking function by engaging the locking pieces 2 and the locking teeth 2a, 1b of the cylindrical member 1 in the backward direction. This restrains the backward movement.

  Further, when an overload from the engine is applied, a force in the backward direction is applied via the front shaft member 31 of the shaft member 3 that receives the locking piece 2 engaged with the cylindrical member 1 by the cam inclined surface 3c. When the received holder spring 6 is compressed and the front shaft member 31 moves backward, overload prevention can be secured.

  Further, in addition to the same operations and effects as in the fourth embodiment, in addition to the structure for attaching the tubular member 1 to the inner wall 201 of the engine body 200 in the fourth embodiment with the U-shaped clamp 13, in the fifth embodiment, Has a mounting structure in which the cylindrical member 1 is directly screwed onto the male threaded portion 207 of the inner wall 201 of the engine body 200, and an overload can be prevented by the separately added holder spring 6 to cope with a stronger load from the engine body 200. can do.

As described above, the fifth embodiment can be applied to a new large engine that performs further high-load operation, and thus the degree of freedom in design is further expanded.
[Embodiment 6]

  FIG. 20 is a longitudinal sectional view showing a tensioner according to a sixth embodiment of the present invention, FIG. 21A is a side view of the locking piece according to the sixth embodiment, FIG. 20B is a plan view of FIG. FIG. 22A is a side view of the shaft member of the sixth embodiment, FIG. 22B is a plan view of FIG. 22A, and FIG. 22C is a left side view of FIG.

  In this embodiment, the ratchet mechanism comprising the locking piece 2, the cam inclined surface 3c of the shaft member 3 and the pressing spring 5 that urges the locking piece 2 in the diameter-expanding direction in the modified embodiment (FIG. 15) of the third embodiment. The other structure is the same as that shown in FIG. 15 except that the structure is different and the structural shape of the rear end portion of the shaft member 3 associated therewith is partially changed. It is the same as the form.

  On the outer peripheral side of the rear end portion of the shaft member 3 of this embodiment, as shown in FIGS. 20 and 22, the rear end side is opened along the axial direction, and a locking piece 2 described later is movably accommodated. A stop piece receiving groove 3m is formed at one location. On the bottom surface near the rear end of the locking piece housing groove 3m, a spring housing hole 3n for housing a pressing spring 5 described later is formed in a direction perpendicular to the axis, that is, in the radial direction. Further, shaft mounting holes 3p for mounting the support shafts 22 that pivotally support the locking pieces 2 are formed on both side surfaces near the front end of the locking piece receiving grooves 3m.

  As shown in FIGS. 20 and 21, the locking piece 2 of this embodiment is axially connected to the locking piece 2 in the first to fifth embodiments via the cam slopes 2 b and 3 c of the shaft member 3. Unlike the form that can be moved, the locking tooth 2a is engraved in the rear half of the outer periphery, and the inclined surface 2g having a downward slope is formed in the front of the figure so that the front half gradually decreases in the axial direction. Yes. Further, an inner peripheral surface (lower end surface in the drawing) 2h is formed in a substantially horizontal plane, a front end surface is formed in an inclined surface 2i tilted forward in the drawing, and both side surfaces are formed in a cleave nut shape having a parallel cut surface 2d. The inclined surface 2g of the rear half of the outer periphery and the inclined surface 2i of the front end surface are respectively formed on the locking teeth 1b and the locking piece receiving grooves 3 on the inner surface of the cylindrical member 1 when the locking piece 2 swings in the diameter reducing direction. It serves as an escape portion that avoids interference with the front end wall that is substantially perpendicular to the axis. Further, a shaft hole 2f through which the support shaft 22 is inserted and rotatably supported is formed in a corner portion between the side surface, that is, the inner peripheral surface 2h of the parallel cut surface 2d and the front end surface 2i. Thus, the effect which arrange | positions the shaft hole 2f of the latching piece 2 in the corner | angular part of the internal peripheral surface 2h and the front-end surface 2i is mentioned later.

  A pressing spring 5 made of a small-diameter compression spring is housed in the spring housing hole 3n at the rear end of the shaft member 3, and the rear end side of the inner peripheral surface 2h of the locking piece 2 is pressed to expand the diameter. Energized in the direction.

  Therefore, in this embodiment, the cam inclined surface 3c of the shaft member 3 in the first to fifth embodiments is different from the locking piece receiving portion that receives the locking piece 2 movably in the axial direction via the cam inclined surface 2b. A support piece 22 that pivotally supports the locking piece receiving groove 3 in the rear end portion of the shaft member 3 and the locking piece 2 in the locking piece receiving groove 3 so as to be swingable in the radial direction pivots the locking piece 2 so as to be swingable. It is the supporting piece support part to be supported.

  In this embodiment, since the locking piece 2 pivotally supported in the locking piece receiving groove 3 so as to be swingable in the radial direction does not move in the axial direction, the presser plate 9 in the modified embodiment of FIG. 15 is omitted. Therefore, it is suitable for a small engine that performs light load operation as a simple type tensioner having a simplified configuration.

  Also in this embodiment having the above-described configuration, the same operations and effects as the above-described modification of FIG.

  When the shaft member 3 is propelled by the ratchet mechanism, the locking piece 2 receiving the reaction force in the axially rearward direction at the locking teeth 1b and 2a of the cylindrical member 1 and the locking piece 2 is supported by the support shaft. Since a rotational torque in the counterclockwise direction shown in the figure is generated with 22 as a fulcrum, it rotates (oscillates) in the diameter-reducing direction against the urging force of the pressing spring 5 against the locking tooth 1b on the inner surface of the cylindrical member 1. Then, the shaft member 3 can be propelled by the locking teeth 2 a getting over the locking teeth 1 b of the cylindrical member 1. When the shaft member 3 moves backward, the locking piece 2 receiving the reaction force forward in the axial direction at the locking teeth 1b and 2a generates a rotational torque in the clockwise direction shown in the drawing with the support shaft 22 as a fulcrum. Therefore, the locking piece 2 is pressed by the locking teeth 1b on the inner surface of the cylindrical member 1 so that the locking piece 2 rotates (swings) in the diameter expanding direction in addition to the urging force of the pressing spring 5, and the locking piece 2 is locked. When the teeth 2a engage with the locking teeth 1b of the cylindrical member 1, the backward movement is restricted. Then, the same operation as in the first and second embodiments can be performed in accordance with the appropriate load state during normal operation of the small engine and the light load state during cold operation.

  In the sixth embodiment, one locking piece 2 is provided on one side with respect to the central axis of the shaft member 3. However, the locking piece 2 is symmetrical with respect to the central axis as appropriate according to the magnitude of the load from the engine. It goes without saying that a plurality of locking pieces 2 can be arranged and provided.

  In the present invention, as the tensioner, combinations other than the embodiment shown in FIGS. 1 to 22 can be freely set, and the cylindrical member 1, the locking piece 2, the shaft member 3, the propulsion spring 4, the pressing spring 5, and the holder The spring 6, case 7, and other components can be arbitrarily changed in shape or combination, and with a simple structure, it is possible to increase the strength of the locking teeth, reduce backlash, reduce the number of parts, and reduce the cost. A tensioner with a high degree of design freedom can be provided.

  In addition, for the compression springs such as the propulsion spring 4, the pressing spring 5, and the holder spring 6, the size and shape of the spring member including the diameter can be arbitrarily changed, thereby adjusting the spring compression force arbitrarily. Can do. Furthermore, these compression springs can be optionally applied any one of a coil spring, a disc spring, a rubber forming body, a resin forming body, and the like.

(A) is the longitudinal cross-sectional view which shows the tensioner of Embodiment 1 of this invention, (b) is the right view of (a), (c) is the sectional view on the AA line of (a). FIG. 3 is an exploded perspective view of a main portion (ratchet mechanism portion) of the tensioner according to the first embodiment. (A) is a side view of the shaft member of Embodiment 1, (b) is a plan view of (a), and (c) is a right side view of (a). single (A) is a side view of the locking piece of Embodiment 1, (b) is a left side view of (a), and (c) is a right side view of (a). (A) is a side view of the rotation prevention board of Embodiment 1, (b) is a top view of (a), (c) is a left view of (a). (A) is a longitudinal cross-sectional view which shows the tensioner of Embodiment 2 of this invention, (b) is the BB sectional drawing of (a). It is a disassembled perspective view of the front-end | tip principal part (ratchet mechanism part) of the tensioner of Embodiment 2. FIG. (A) is a side view of the shaft member of Embodiment 2, (b) is a plan view of (a), and (c) is a right side view of (a). (A) is a side view of the locking piece of Embodiment 2, (b) is a left side view of (a), and (c) is a right side view of (a). (A) is a side view of the rotation prevention board of Embodiment 2, (b) is a top view of (a), (c) is a left view of (a). (A) is a side view of the presser plate of Embodiment 2, (b) is a left side view of (a). The operation of the tensioner of Embodiment 2 is shown, (a) is an overload state during hot engine operation, (b) is an appropriate load state during normal engine operation, and (c) is a light load state during cold engine operation. FIG. It is a longitudinal cross-sectional view which shows the tensioner of Embodiment 3 of this invention. It is a disassembled perspective view of the front-end | tip principal part (ratchet mechanism part) of the tensioner of Embodiment 3. FIG. FIG. 10 is a longitudinal sectional view showing a tensioner according to a modification of the third embodiment. (A) is a side view of the shaft member of FIG. 15, (b) is a plan view of (a), and (c) is a left side view of (a). (A) is a side view which shows the tensioner of Embodiment 4 of this invention, (b) is a top view of (a). (A) is a top view of the bracket of Embodiment 4, (b) is a left view of (a). (A) is a side view which shows the tensioner of Embodiment 5 of this invention, (b) is a top view of (a). It is a longitudinal cross-sectional view which shows the tensioner of Embodiment 6 of this invention. (A) is a side view of the locking piece of Embodiment 6, (b) is a plan view of (a), and (c) is a left side view of (a). (A) is a side view of the shaft member of Embodiment 6, (b) is a plan view of (a), and (c) is a left side view of (a). It is an example of the layout figure of the state which mounted | wore the engine main body with the tensioner. It is a longitudinal cross-sectional view which shows an example of the conventional tensioner. (A) is an operation explanatory view of the tensioner propelling member of FIG. 24 in the locked state with the locking piece, and (b) is a sectional view taken along the line DD of (a). (A) is action | operation explanatory drawing of the locking piece diameter expansion state at the time of the propulsion member advance of FIG. 25, (b) is the EE sectional view taken on the line of (a).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylindrical member 1b, 2a Locking tooth 2 Locking piece 2b Cam slope 3 Shaft member 3c Cam slope (locking piece receiving part)
3m Locking piece receiving groove 3n Spring receiving hole 3p Shaft mounting hole (Locking piece support part)
4 propulsion spring 5 pressure spring 6 holder spring 7 case 8 anti-rotation plate 8 'washer 9 presser plate 22 support shaft 200 engine body 201 inner wall 207 male thread

Claims (6)

A cylindrical member formed with a plurality of locking teeth;
One or more locking pieces formed with locking teeth that engage with the locking teeth;
A locking member receiving portion or a locking piece support portion that receives the locking piece that engages with the cylindrical member, and a shaft member disposed inside the cylindrical member, and
Either the cylindrical member or the shaft member is a propulsion member that is propelled forward and backward by an urging force,
The propulsion member is allowed to advance by moving the locking piece in the diameter reducing direction and overcoming the locking teeth of the cylindrical member, and the locking piece moves in the diameter increasing direction to move the cylindrical member. A tensioner provided with a ratchet mechanism for restraining the propulsion member from retreating by engaging with a locking tooth. The ratchet mechanism is
A cam slope formed on the locking piece receiving portion and formed to expand the diameter of the locking piece in a direction of engaging with the locking teeth of the tubular member;
The tensioner according to claim 1, further comprising: a pressing spring that presses the locking piece against the cam slope of the shaft member and urges the locking piece in the diameter increasing direction. The ratchet mechanism is
A locking piece receiving groove formed in the locking piece support portion for receiving the locking piece;
A support shaft for pivotally supporting the locking piece in the locking piece receiving groove so as to be swingable in the radial direction;
The tensioner according to claim 1, further comprising: a pressing spring that urges the locking piece in the diameter increasing direction.   The cylindrical member and the locking teeth of the locking piece are either flat teeth of the lead 0 formed in a groove shape perpendicular to the axial direction, single threads, or multi-threaded teeth. Item 4. The tensioner according to any one of Items 1 to 3.   The tensioner according to any one of claims 1 to 4, wherein an outer surface of the shaft member is disposed on an inner surface of the cylindrical member so as to be relatively movable in an axial direction through a radial gap. The tensioner according to any one of claims 1 to 5, further comprising a hydraulic pressure source that applies hydraulic pressure in a direction in which the propulsion member propels.

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